An important factor for determining the quality of a wound sheet of material is the winding speed. Generally, winding speed can be used to control the winding tension and/or the winding density. The winding speed is especially important for sheet materials including film and adhesive combinations where the majority of the adhesive lies in the recesses of the film. Although various mechanisms and apparatuses have been proposed for winding and unwinding operations, problems have been presented in maintaining a uniform wound product.
In various manufacturing operations for producing textiles, felts, papers, films, etc., it is necessary to wind a sheet of material into a roll. Where the sheet of material is a uniform and repeatable rolled consumer product, the roll may be referred to as a log. Consumer product logs are often much smaller than the commercial rolls used in other applications. Further, sheets of material such as paper products or film-adhesive combinations may have little or no tension applied at certain points in the rolling process. The winding quality and material properties such as thickness and appearance are strongly influenced by the tension that is present in the sheet of material during the winding operation. This is particularly true for the winding of adhesively coated sheets of material such as film-adhesive combinations. During winding, the process tension may result in some of the wound layers bonding together at various locations in the wind. It has been found that a better, faster and more repeatable control mechanism is possible through controlling the material log speed with a reference profile that is adjustable based upon measured process parameters.
Despite the efforts to improve the winding of material, there remains a need for improvements in the speed, control, and effectiveness of devices for producing wound consumer logs of material.
Several patents describe alternative winding approaches for various purposes. Such efforts are described in U.S. Pat. No. 4,588,138, issued to Spencer, U.S. Pat. No. 4,508,284 issued to Kataoka, U.S. Pat. No. 4,744,526 issued to Kremar, U.S. Pat. No. 5,611,500 issued to Smith, U.S. Pat. No. 3,934,837 issued to Keilhack, et al., U.S. Pat. No. 6,189,824 issued to Stricker, U.S. Pat. No. 4,883,233 issued to Saukkonen, et al. and U.S. Pat. No. 6,189,825 issued to Mathieu, et al.
An object of the present invention is to provide a winding apparatus for paper, textile, plastic, or other sheets of material, which has advantageous winding characteristics for consumer size logs using at least one reference profile. Another object of the invention is to manufacture logs with a smaller diameter variation. It is also an object of the present invention to provide a log with a more consistent wind tension such that the force required to unwind the sheet of material from the log is relatively constant throughout the log. This is especially important for film-adhesive combinations where the bonding of the sheets to one another inside the log can be a problem. Further objects, features, and advantages of the invention will become apparent from the detailed description that follows.